Extended support for HTTP proxy in driver options (#1424)

README.md

@@ -160,6 +160,7 @@ conn.SetConnMaxLifetime(time.Hour)
 * read_timeout - a duration string is a possibly signed sequence of decimal numbers, each with optional fraction and a unit suffix such as "300ms", "1s". Valid time units are "ms", "s", "m" (default 5m).
 * max_compression_buffer - max size (bytes) of compression buffer during column by column compression (default 10MiB)
 * client_info_product - optional list (comma separated) of product name and version pair separated with `/`. This value will be pass a part of client info. e.g. `client_info_product=my_app/1.0,my_module/0.1` More details in [Client info](#client-info) section.
+* http_proxy - HTTP proxy address
 
 SSL/TLS parameters:
 
@@ -174,6 +175,8 @@ clickhouse://username:password@host1:9000,host2:9000/database?dial_timeout=200ms
 
 ### HTTP Support (Experimental)
 
+**Note**: using HTTP protocol is possible only with `database/sql` interface.
+
 The native format can be used over the HTTP protocol. This is useful in scenarios where users need to proxy traffic e.g. using [ChProxy](https://www.chproxy.org/) or via load balancers.
 
 This can be achieved by modifying the DSN to specify the HTTP protocol.
@@ -203,7 +206,19 @@ conn := clickhouse.OpenDB(&clickhouse.Options{
 })
 ```
 
-**Note**: using HTTP protocol is possible only with `database/sql` interface.
+#### Proxy support
+
+HTTP proxy can be set in the DSN string by specifying the `http_proxy` parameter.
+(make sure to URL encode the proxy address)
+
+```sh
+http://host1:8123,host2:8123/database?dial_timeout=200ms&max_execution_time=60&http_proxy=http%3A%2F%2Fproxy%3A8080
+```
+
+If you are using `clickhouse.OpenDB`, set the `HTTProxy` field in the `clickhouse.Options`.
+
+An alternative way is to enable proxy by setting the `HTTP_PROXY` (for HTTP) or `HTTPS_PROXY` (for HTTPS) environment variables.
+See more details in the [Go documentation](https://pkg.go.dev/net/http#ProxyFromEnvironment).
 
 ## Compression
 

clickhouse_options.go

@@ -22,6 +22,7 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net"
+	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
@@ -121,6 +122,8 @@ type DialResult struct {
 	conn *connect
 }
 
+type HTTPProxy func(*http.Request) (*url.URL, error)
+
 type Options struct {
 	Protocol   Protocol
 	ClientInfo ClientInfo
@@ -143,7 +146,10 @@ type Options struct {
 	HttpHeaders          map[string]string // set additional headers on HTTP requests
 	HttpUrlPath          string            // set additional URL path for HTTP requests
 	BlockBufferSize      uint8             // default 2 - can be overwritten on query
-	MaxCompressionBuffer int               // default 10485760 - measured in bytes  i.e. 10MiB
+	MaxCompressionBuffer int               // default 10485760 - measured in bytes  i.e.
+
+	// HTTPProxy specifies an HTTP proxy URL to use for requests made by the client.
+	HTTPProxyURL *url.URL
 
 	scheme      string
 	ReadTimeout time.Duration
@@ -302,6 +308,12 @@ func (o *Options) fromDSN(in string) error {
 					version,
 				})
 			}
+		case "http_proxy":
+			proxyURL, err := url.Parse(params.Get(v))
+			if err != nil {
+				return fmt.Errorf("clickhouse [dsn parse]: http_proxy: %s", err)
+			}
+			o.HTTPProxyURL = proxyURL
 		default:
 			switch p := strings.ToLower(params.Get(v)); p {
 			case "true":

clickhouse_options_test.go

@@ -19,10 +19,12 @@ package clickhouse
 
 import (
 	"crypto/tls"
+	"net/url"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // TestParseDSN does not implement all use cases yet
@@ -467,6 +469,19 @@ func TestParseDSN(t *testing.T) {
 			},
 			"",
 		},
+		{
+			"http protocol with proxy",
+			"http://127.0.0.1/?http_proxy=http%3A%2F%2Fproxy.example.com%3A3128",
+			&Options{
+				Protocol:     HTTP,
+				TLS:          nil,
+				Addr:         []string{"127.0.0.1"},
+				Settings:     Settings{},
+				scheme:       "http",
+				HTTPProxyURL: parseURL(t, "http://proxy.example.com:3128"),
+			},
+			"",
+		},
 	}
 
 	for _, testCase := range testCases {
@@ -484,3 +499,9 @@ func TestParseDSN(t *testing.T) {
 		})
 	}
 }
+
+func parseURL(t *testing.T, v string) *url.URL {
+	u, err := url.Parse(v)
+	require.NoError(t, err)
+	return u
+}

conn_http.go

@@ -201,8 +201,13 @@ func dialHttp(ctx context.Context, addr string, num int, opt *Options) (*httpCon
 	query.Set("default_format", "Native")
 	u.RawQuery = query.Encode()
 
+	httpProxy := http.ProxyFromEnvironment
+	if opt.HTTPProxyURL != nil {
+		httpProxy = http.ProxyURL(opt.HTTPProxyURL)
+	}
+
 	t := &http.Transport{
-		Proxy: http.ProxyFromEnvironment,
+		Proxy: httpProxy,
 		DialContext: (&net.Dialer{
 			Timeout: opt.DialTimeout,
 		}).DialContext,

examples/std/connect.go

@@ -20,6 +20,8 @@ package std
 import (
 	"database/sql"
 	"fmt"
+	"net/url"
+
 	"github.com/ClickHouse/clickhouse-go/v2"
 )
 
@@ -50,3 +52,41 @@ func ConnectDSN() error {
 	}
 	return conn.Ping()
 }
+
+func ConnectUsingHTTPProxy() error {
+	env, err := GetStdTestEnvironment()
+	if err != nil {
+		return fmt.Errorf("failed to get test environment: %w", err)
+	}
+
+	proxyURL, err := url.Parse("http://proxy.example.com:3128")
+	if err != nil {
+		return fmt.Errorf("failed to parse proxy URL: %w", err)
+	}
+
+	conn := clickhouse.OpenDB(&clickhouse.Options{
+		Addr: []string{fmt.Sprintf("%s:%d", env.Host, env.Port)},
+		Auth: clickhouse.Auth{
+			Database: env.Database,
+			Username: env.Username,
+			Password: env.Password,
+		},
+		HTTPProxyURL: proxyURL,
+	})
+	return conn.Ping()
+}
+
+func ConnectUsingHTTPProxyDSN() error {
+	env, err := GetStdTestEnvironment()
+	if err != nil {
+		return fmt.Errorf("failed to get test environment: %w", err)
+	}
+
+	urlEncodedProxyURL := url.QueryEscape("http://proxy.example.com:3128")
+
+	conn, err := sql.Open("clickhouse", fmt.Sprintf("clickhouse://%s:%d?username=%s&password=%s&http_proxy=%s", env.Host, env.Port, env.Username, env.Password, urlEncodedProxyURL))
+	if err != nil {
+		return err
+	}
+	return conn.Ping()
+}